/*
 * Copyright (C) 2007-2010 Geometer Plus <contact@geometerplus.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 */

package org.geometerplus.zlibrary.core.xml;

import org.geometerplus.zlibrary.core.util.ZLArrayUtils;

final class ZLMutableString {
    char[] myData;
    int myLength;

    ZLMutableString(int len) {
        myData = new char[len];
    }

    ZLMutableString() {
        this(20);
    }

    ZLMutableString(ZLMutableString container) {
        final int len = container.myLength;
        myData = ZLArrayUtils.createCopy(container.myData, len, len);
        myLength = len;
    }

    public void append(char[] buffer, int offset, int count) {
        final int len = myLength;
        char[] data = myData;
        final int newLength = len + count;
        if (data.length < newLength) {
            data = ZLArrayUtils.createCopy(data, len, newLength);
            myData = data;
        }
        System.arraycopy(buffer, offset, data, len, count);
        myLength = newLength;
    }

    public void clear() {
        myLength = 0;
    }

    public boolean equals(Object o) {
        final ZLMutableString container = (ZLMutableString) o;
        final int len = myLength;
        if (len != container.myLength) {
            return false;
        }
        final char[] data0 = myData;
        final char[] data1 = container.myData;
        for (int i = len; --i >= 0;) {
            if (data0[i] != data1[i]) {
                return false;
            }
        }
        return true;
    }

    public int hashCode() {
        final int len = myLength;
        final char[] data = myData;
        int code = len * 31;
        if (len > 1) {
            code += data[0];
            code *= 31;
            code += data[1];
            if (len > 2) {
                code *= 31;
                code += data[2];
            }
        } else if (len > 0) {
            code += data[0];
        }
        return code;
    }

    public String toString() {
        return new String(myData, 0, myLength).intern();
    }
}
